#include<iostream> #include<cstdio> #include<cstring> #include<cmath> using namespace std; int main(){ int a; cin>>a; a/=10; switch(a){ case 10: cout<<"S"<<endl; break; case 9: cout<<"A"<<endl; break; case 7:case 8: cout<<"B"<<endl; break; case 6: cout<<"C"<<endl; default: cout<<"D"<<endl; } }